Find in Project with Ack

Question

Trying to find in Project with Projectile.. In the Projectile menu i have

• Find in project (grep)
• Find in project (ack)

Grep works but if i try ack i get..

-*- mode: ack-and-a-half; default-directory: "~/Desktop/proj/" -*- Ack started at Mon Dec 29
16:39:24
 --ignore-dir=.idea --ignore-dir=.eunit --ignore-dir=.git --ignore-dir=.hg --ignore-dir=.fslckout --ignore-dir=.bzr --ignore-dir=_darcs --ignore-dir=.tox --ignore-dir=.svn --ignore-dir=build --ignore-file=is:TAGS --nocolor --nogroup --column --smart-case --env -- audio zsh:1: command not found: --ignore-dir=.idea
Ack exited abnormally with code 127 at Mon Dec 29 16:39:24

I haven't done much to get it to work except install ack-and-a-half and ag.el from MELPA (I'm confused about which I want / how to replace one with the other) but don't know how to proceed or debug - I can't find any documentation

ack and ag both work from the terminal and my homebrew dir has been added to the emacs path

any help for an emacs begginer is much appreciated

Answer 1

ack-and-a-half is now abandonware. I don't think plain projectile-ack is still functional in current Projectile -- maybe you should try ag. If you really want ack, you could give helm-projectile-ack a try.

Answer 2

According to the source, I would reckon ack-and-a-half-executable is nil. This would explain the output you get. Again from the source, it would appear that ack is not visible to Emacs.

Note the TODO:

; TODO Determine how to fall back to using ack-grep if ack is not found.
(defcustom ack-and-a-half-executable (executable-find "ack")
  "*The location of the ack executable"
  :group 'ack-and-a-half
  :type 'file)

;...

(compilation-start
  (mapconcat 'identity
             (nconc (list ack-and-a-half-executable)
                    arguments)
             " ")
  'ack-and-a-half-mode))

See exec-path and $PATH for information on how to show Emacs where ack is.

Note that @TuDo's answer stands as good advice -- drop ack-and-a-half in favor of another solution (such as helm-ag or simply ag.el) -- but I hope this answer actually diagnosis the problem for you or anyone else who has become dependent on ack-and-a-half.

Answer 3

• The ack utility is better than the grep utility – but apt-get install ack installs a japanese kanji package!

• Do this instead: Use pkg-divert to force the package name to ack:

  dpkg-divert --local --divert /usr/bin/ack --rename --add /usr/bin/ack-grep
  apt-get install ; apt-get install ack-grep -f -y --force-yes
  

• For more see: http://betterthangrep.com

• Suggest installing the Perl App::Ack package too.